MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...

FM/UOJ
[Demonstration by Biopack system]
Instrument:
Spirometer
Method:
The subject sits comfortably in a chair, facing away from the spirometer. Turn the
union of the tubes to the ‘spirometer’ position and flush the breathing chamber with fresh
air by raising and lowering the inverted drum. Raise the inverted cylinder half way up
and turn the outlet to ‘air’ which closes the inner tube and allows the subject to breathe
from atmosphere. The subject applies the mouthpiece and breathes through the
corrugated tube. The nose of the subject is close by a nose clip. Wait until the subject gets
used to the apparatus. Instruct the subject about the procedures to be followed before
each measurement. Make sure that the measurements are completed soon or disconnect
the subject from the spirometer and collect air in the drum.
Tidal volume:
Switch on the Kymograph of the spirometer at low speed and turn the union
‘spirometer’ which makes the subject breathe from and into the spirometer.
Expiratory reserve volume:
Ask the subject to expel all possible air out of the lungs and breathe as usual:
make two recordings.
Inspiratory reserve volume:
Ask the subject to inhale as much air as possible and breathe as usual make two
recordings.
Vial capacity:
Ask the subject to inhale as much air as possible and expel as much as possible
and then breathe as usual: make two recordings.
Forced vital capacity:
Ask the subject to inhale as much air as possible and increase the speed of the
recording drum (25 mm/sec). Ask the subject to expel air as much and as rapidly as
possible.
Calculate the forced expiratory air volume in the first second and express it as a
percentage of the total air expelled (FEV 1 ).
Method of prediction of lung volumes:
Lung volume depends on the build of a person. The lung volume therefore, may
be expected to be related to the height and weight of a person. Formula give below are
used to predict the volumes.
VC
= 0.064 X [height (cm)] – 0.031 X (age) – 5.335 Male
= 0.052 X [height (cm)] – 0.018 X (age) – 4.36 Female
Total lung capacity (TLC)
Respiration
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